When shopper Ruth Lawson tweeted Debenhams with her complaint, the Department store chain, which has 192,000 Twitter followers, replied that it was not acceptable and that the complaint had been fed back to management.

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But when the Mail shared the story on its Facebook page, many more people were quick to agree - with one describing the shop as a sweat box and another saying she once thought she was going to pass out in there.

Georgie Lou wrote: "I was on the first floor with my kids yesterday and the poor things were so frazzled and thirsty after just 5 minutes, that we had to leave."

Julie Thomson said: "I go in regularly and it's unbearable. I see staff that look like they're about to pass out."